Connect 8 6-foot LED strips in parallel, powered by battery

Thread Starter

dyudkin

Joined Feb 8, 2021
14
(somehow my response was missing a huge portion)
(screwed up again. One more edit)

Adding flashing can be done by wiring a flashing module in series with the power, just like the switch.

The decision is to build or buy. I hinted at this above, when I suggested using a BJT/MOSFET in the switch location, driven by electronics. You could build a 555 based timing circuit to drive the transistor switch.

But, I suspect that this may be a strain on your skills. Even if we supply a solution, can you read a schematic, wire ICs, transistors, resistors, capacities and relays? Even simpler, can you solder?

Or, you can buy a flasher module. One which has selectable patterns and is used to drive LED lights, can cost you $30-$40. Or an automotive flasher relay used in turn signals can be used at a cost of $10-$20. If the flashing rate is acceptable.

The ultimate solution which you can ignore is microprocessor based. Someone else may suggest it, but then you add on a learning curve for programming and uploading your program. I don’t recommend this solution for you.

If any of these ideas appeal to you, let me know. Then I can provide more detail.
Hi there -

Thanks for this thorough explanation. You're right to presume that reading a schematic would be beyond my skills. I am essentially looking for the simplest possible solution to the problem. The most I can be expected to do is to solder 2-4 wires to clearly marked connectors. Aside from that I'm looking for a set of devices with clearly marked "input" and "output" cables that transform an electric current into blinky lights :)
 

Thread Starter

dyudkin

Joined Feb 8, 2021
14
Well maybe if you defined exactly what you want, someone could make you a BOM.
I'm sorry; I truly don't know how to be more specific than I have already been. Do you need more details about the type of lights I'm looking for? Lights that turn on and off every half second. Ideally purple in color. What other details should I provide?
 

Reloadron

Joined Jan 15, 2015
7,580
Here is what this comes down to. You can do just about any effects you want with LED lights. They do make over the counter controllers with all sorts of effects built in. The problem is a controller module can only handle so much load. Each string of LEDs becomes a load and the total current becomes the sum of all the loads. You can have anything you want but as we add features like color changing or fade in and fade out things get more complex and if you plan a DIY (Do It Yourself) complexity really can have a steep learning curve. Even using turn key solutions can get complex.

Paralleling 8 strings of single color like warm white LEDs is pretty simple and even having them just flash On/Off at some interval is not bad but as we want more features things can get more complex and cost gets added. The artist draws a layout and defines what they want to happen. Clean sheet of paper with eight lines extending out from a circle in the center. One line every 45 degrees. Next what do the lines do in what sequence? You can have any sequence and time line you want but keep complexity in mind. These are the specifics.

So you want Purple LEDs. That's a specific and you want them to turn ON/Off every 1/2 second so On for 1/2 second and Off for 1/2 second. That's another specific. These are purple LEDs (single color) which use 24 volt strings so you are looking at two 12 volt (series) or one 24 volt battery. That was at a glance, you may find 12 volt purple strings.

Ron
 

Thread Starter

dyudkin

Joined Feb 8, 2021
14
Here is what this comes down to. You can do just about any effects you want with LED lights. They do make over the counter controllers with all sorts of effects built in. The problem is a controller module can only handle so much load. Each string of LEDs becomes a load and the total current becomes the sum of all the loads. You can have anything you want but as we add features like color changing or fade in and fade out things get more complex and if you plan a DIY (Do It Yourself) complexity really can have a steep learning curve. Even using turn key solutions can get complex.

Paralleling 8 strings of single color like warm white LEDs is pretty simple and even having them just flash On/Off at some interval is not bad but as we want more features things can get more complex and cost gets added. The artist draws a layout and defines what they want to happen. Clean sheet of paper with eight lines extending out from a circle in the center. One line every 45 degrees. Next what do the lines do in what sequence? You can have any sequence and time line you want but keep complexity in mind. These are the specifics.

So you want Purple LEDs. That's a specific and you want them to turn ON/Off every 1/2 second so On for 1/2 second and Off for 1/2 second. That's another specific. These are purple LEDs (single color) which use 24 volt strings so you are looking at two 12 volt (series) or one 24 volt battery. That was at a glance, you may find 12 volt purple strings.

Ron
This is very helpful. Thank you for patiently walking me through the process, and giving me a clearer picture of what "specifics" means.

Suppose, for the sake of argument, I started with a 12V, 35 AH battery, like this one. Suppose also that I wanted to run
8 .5-second-blinking purple LEDs, like these, from this central power source for as long as the battery will last. What sort of connecting device would i need to connect these cut LED strips to the central battery source? Is that a specific-enough question?
 

Reloadron

Joined Jan 15, 2015
7,580
Here is the problem. The link does not mention the current draw? They do mention 3 AA batteries so I can see 4.5 volts supply but no mention of the load current so I can't predict how long a 35 AH battery will last. Figure it this way, in theory and only in theory, a 35 Amp Hour battery will deliver 35 amps to a load at its rated voltage for one hour, it will deliver 17.5 amps for two hours and 8.75 amps for four hours. It will deliver 1 amp for 35 hours so you see how this is going. In theory it would deliver 70 amps for 1/2 hour or 140 amps for 1/4 hour. Batteries will seldom meet their ratings under heavy load but you get the idea.

Depending on the type strip you can cut strips to length you want. Then you place the strips in parallel. The load current will be the sum of all the strips.

Ron
 

Thread Starter

dyudkin

Joined Feb 8, 2021
14
Here is the problem. The link does not mention the current draw? They do mention 3 AA batteries so I can see 4.5 volts supply but no mention of the load current so I can't predict how long a 35 AH battery will last. Figure it this way, in theory and only in theory, a 35 Amp Hour battery will deliver 35 amps to a load at its rated voltage for one hour, it will deliver 17.5 amps for two hours and 8.75 amps for four hours. It will deliver 1 amp for 35 hours so you see how this is going. In theory it would deliver 70 amps for 1/2 hour or 140 amps for 1/4 hour. Batteries will seldom meet their ratings under heavy load but you get the idea.

Depending on the type strip you can cut strips to length you want. Then you place the strips in parallel. The load current will be the sum of all the strips.

Ron
OK this is helpful again! I have enough to work on for the time being. Very grateful.
 

djsfantasi

Joined Apr 11, 2010
9,188
Ok, you have several requirements. Based on 12V operation and purple LED strips, these may be a better match for you.

But we need to do some calculations to determine if a 12V battery can run them for 8 hours. Is 8 hours a hard requirement? Could 6 hours be ok? What is the minimum amount of time that you need?

I can’t run these numbers tonight.

Will flashing at the same rate as a car’s turn signal be acceptable. I think it’s close..

Then one of these could be used. And that one can have its flashing rate adjusted with a screwdriver.

Wiring is simple. Battery + to switch. Switch to flasher module. Flasher module to + side of all trips.

Battery - to - side of all LED strips.

That’s it. Once we confirm the current draw and battery life time. You’ll also need to recharge the battery after each use.

Minimal soldering. Battery terminals to connect the battery. Get some connectors that fit the relay. Solder the switch. Use terminal strips to connect the strips in parallel. I’d also buy connectors for the strips...

But we can get into that level of detail later, once you answer the design specifications. Battery life... Flasher suitability... Color is good...
 

Thread Starter

dyudkin

Joined Feb 8, 2021
14
Ok, you have several requirements. Based on 12V operation and purple LED strips, these may be a better match for you.

But we need to do some calculations to determine if a 12V battery can run them for 8 hours. Is 8 hours a hard requirement? Could 6 hours be ok? What is the minimum amount of time that you need?

I can’t run these numbers tonight.

Will flashing at the same rate as a car’s turn signal be acceptable. I think it’s close..

Then one of these could be used. And that one can have its flashing rate adjusted with a screwdriver.

Wiring is simple. Battery + to switch. Switch to flasher module. Flasher module to + side of all trips.

Battery - to - side of all LED strips.

That’s it. Once we confirm the current draw and battery life time. You’ll also need to recharge the battery after each use.

Minimal soldering. Battery terminals to connect the battery. Get some connectors that fit the relay. Solder the switch. Use terminal strips to connect the strips in parallel. I’d also buy connectors for the strips...

But we can get into that level of detail later, once you answer the design specifications. Battery life... Flasher suitability... Color is good...
Wow you are going above and beyond and I will try to meet you halfway on this. To answer your questions:

- 8 hours is not a hard requirement. 6 will suffice.
- A flasher at that rate would certainly be a good starting point, and having a bit of customizability with the screwdriver is a bonus
- Those lights look great. I don't see an Amperage draw on those either but maybe I'm not looking in the right place.
- Not sure what "connectors that fit the relay" will mean, and not sure what sort of switch is appropriate but overall this sounds like a great sketch!
 

djsfantasi

Joined Apr 11, 2010
9,188
Wow you are going above and beyond and I will try to meet you halfway on this. To answer your questions:

- 8 hours is not a hard requirement. 6 will suffice.
- A flasher at that rate would certainly be a good starting point, and having a bit of customizability with the screwdriver is a bonus
- Those lights look great. I don't see an Amperage draw on those either but maybe I'm not looking in the right place.
- Not sure what "connectors that fit the relay" will mean, and not sure what sort of switch is appropriate but overall this sounds like a great sketch!
Good! I’ll get back to you tomorrow
 

Kjeldgaard

Joined Apr 7, 2016
476
I had some ideas on whether you could use one or more PIR (Passive Infra Red) sensors to only turn on the LED lighting when there are people nearby?

But remember to mount a suitable size fuse directly on the positive terminal of the battery - lead-acid batteries can supply an awful lot of power for quite some time.
 

BobTPH

Joined Jun 5, 2013
9,296
The lights linked in post #28 are speced at 4.8W / m.

8 legs at 5 ft each is 40 ft or abot 12 m.

This is 57.6 W or, at 12V, 4.8A.

Your 35Ah battery would, theoretically, last over 7 hours. More likely around 4 or 5 in reality.

Bob
 
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